Apparatus using a method for recording digital data including a data conversion or format conversion, and apparatus using the method

ABSTRACT

A plurality of digital signals having total data rates of n bit/s or less are input to a digital recording device recording digital signals having a data rate of n bit/s. The digital signals are subjected to format-conversion for the digital recording device to be recorded therein. Furthermore, signals having a data rate of n/i 1  bit/s or less are subjected to format-conversion to be recorded i 1  times in the digital recording device. In the case where the data rate of the digital signals to be input is n/j bit/s, the digital signals are subjected to format-conversion so that the amount of data capable of being recorded per unit time is decreased by i/j; thus, the digital signals are recorded for a long period of time under the condition that the data recording time is prolonged j times. Furthermore, when input data to be recorded on a magnetic tape at a normal data rate by using a magnetic head mounted on a rotary cylinder is recorded, the recording device of the present invention makes it possible to select a plurality of types of track angles generated by the rotation number of the cylinder, the tape traveling speed, and the like.

This application is a divisional of U.S. patent application Ser. No.08/893,612 filed on Jul. 10, 1997, now U.S. Pat. No. 6,147,823, which isa file wrapper continuation application of U.S. patent application Ser.No. 08/323,140 filed Oct. 14, 1994 (abandoned).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for recording and/orreproducing digital data having a plurality of kinds of rates, and amethod for reproducing the same.

2. Description of the Related Art

In recent years, various kinds of digital video cassette recorders(hereinafter, referred to as DVCRs) for recording video signals such asTV signals in digital form have been developed. However, since videosignals contain a great amount of information, in the case where thevideo signals are recorded in digital form in a storage medium such as atape, a long recording time is required. In view of such a problem, amethod for recording video signals, which are subjected to highefficiency coding, in digital form has been proposed, for example in theInternational Conference on Consumer Electronics (ICCE) Jun. 6-9, 1989,Digest of Technical Papers WPM8.6 “AN EXPERIMENTAL STUDY ON A HOME-USEDIGITAL VTR”.

In the past, DVCRs record input video signals in synchronization with afield frequency thereof. More specifically, a magnetic head mounted in arotary cylinder rotating in synchronization with the field frequencyrecords video signals in tracks each having a track angle predeterminedin accordance with set standards.

DVCRs use a rotary cylinder for the purpose of enhancing a recordingdensity, and record data in tracks so as to be disposed on a magnetictape in the diagonal direction of a magnetic tape traveling direction.For example, when a magnetic tape is wrapped around a rotary cylinderprovided with two magnetic heads by about 180 degrees and the rotarycylinder rotates at a speed of 9000 rpm (rotation per minute), 18000tracks are recorded on the magnetic tape per minute.

In general, DVCRs reproduce data in the same state as in the recordedstate, except for special reproduction such as scene search, still, andslow reproductions. If data is reproduced in the state different fromthe recorded state, normal reproduction cannot be obtained. Thus, in thecase of producing DVCRs, mechanical design specifications such as atrack angle and a tape traveling speed should be strictly observed.

Since there are various kinds of high efficiency coding, the data rateafter being subjected to high efficiency coding takes various values.Particularly in pre-recorded soft tapes, etc., the data rate is requiredto be decreased by high efficiency coding for the purpose of reducingtape cost.

In recent years, studies to supply digital video signals at a very lowdata rate in video services utilizing a digital TV broadcasting, a CATV,a telephone, etc. have been made. For example, the data rate of DVCRsfor broadcasting is very high, i.e., 270 Mbit/s; however, a method fortransmitting data after decreasing the data rate to 3 to 12 Mbit/s byfiltering, high efficiency coding, etc. and a method for recording dataafter decreasing the data rate to 25 Mbit/s have been put into practicaluse. Furthermore, regarding TV signals, in addition to the NTSC systemand the PAL system, 1125 line-60 field system and 1250 line-50 fieldsystem have been put into practical use.

In the case where a plurality of data rates are obtained depending uponTV signal systems or high efficiency coding methods after coding, arecording method and a reproducing method suitable for each data rateare required.

In general, the recording density and track pitch of the magnetic tapeare respectively kept at nearly predetermined levels. Thus, the numberof tracks and the tape traveling speed per predetermined period of timeare increased in proportion to the data rate. When data is recorded at adata rate different from a normal recording data rate, a signalprocessing circuit and a device having a completely different cylinderconstruction are required. It is desired that data in one tape is copiedto another tape for a short period of time. In particular, when a greatamount of pre-recorded soft tapes, etc. are produced, it is desired tocopy data at a data rate higher than normal for a short period of timeso as to shorten the time for producing the tapes.

SUMMARY OF THE INVENTION

The method for recording digital data of the present invention by usinga recording device recording a data stream having a predetermined datarate of n bit/s (n is a positive number) on a recording medium,comprises the steps of:

performing a data conversion step by receiving a plurality of input datastreams having total data rates of n bit/s or less and converting theplurality of input data streams into a single output data stream havinga data rate of n bit/s or less; and

performing a data recording step by recording the single output datastream.

Alternatively, the method for recording digital data of the presentinvention by using a recording device recording a data stream having apredetermined data rate of n bit/s (n is a positive number) on arecording medium, comprises the steps of:

performing a data conversion step by receiving a single input datastream having a data rate of n/i₁ bit/s (n is a positive number, and i₁is an integer of 2 or more) and converting the single input data streaminto a single output data stream having a data rate of n bit/s or less;and

performing a data recording step by recording the single output datastream for i₁ times.

In one embodiment of the present invention, the plurality of input datastreams include i₂ data streams each having a data rate of n/i₂ bit/s (nis a positive number, and i₂ is an integer of 2 or more) or less.

In another embodiment of the present invention, the data conversion stepincludes the step of receiving i₃ input data streams each having a datarate of n/i₃/i₄ bit/s (n is a positive number, and i₃ and i₄ areintegers of 2 or more) and converting the plurality of input datastreams into the single output data stream having a data rate of n/i₄bit/s, and

the data recording step includes the step of recording the single outputdata stream for i₄ times.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating the numberof the input data streams on the recording medium.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating the numberof the input data streams on an auxiliary storage medium provided in acassette accommodating the recording medium.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating the numberof the input data streams and the number of repetition of recording onthe recording medium.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating the numberof the input data streams and the number of repetition of recording onan auxiliary storage medium provided in a cassette accommodating therecording medium.

Alternatively, the method for recording digital data of the presentinvention by using a recording device having a head mounted on a rotarycylinder, the recording device recording a data stream having apredetermined data rate of n bit/s (n is a positive number) on atraveling recording medium, comprises the steps of:

performing a data recording step by receiving an input data streamhaving a data rate of n/j bit/s or less (j is an integer of 2 or more),setting a traveling speed of the recording medium to be 1/j of a standard traveling speed and recording the output data stream on therecording medium by 1/j of scan times of the recording medium by thehead.

In one embodiment of the present invention, the recording deviceincludes paired heads, the paired heads are respectively provided so asto be symmetric with respect to a rotation axis of the rotary cylinderand have different azimuths, the recording device records the outputdata stream by helically scanning the recording medium, and the j is anodd number.

In another embodiment of the present invention, the data recording stepincludes the step of recording digital data indicating a value of the jon the recording medium.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating a value ofthe j on an auxiliary storage medium provided in a cassetteaccommodating the recording medium.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating a value ofthe j on the recording medium.

In still another embodiment of the present invention, the data recordingstep includes the step of recording digital data indicating a value ofthe j on an auxiliary storage medium provided in a cassetteaccommodating the recording medium.

Alternatively, the method for recording digital data of the presentinvention by using a recording device recording a data stream having apredetermined data rate of n bit/s (n is a positive number) on arecording medium, comprises the step of:

performing a data recording step by receiving a data stream having adata rate of n×(k₁/k₂) bit/s (k₁, and k₂ are integers of 2 or more, andk₁<k₂), setting a traveling speed of the recording medium to be k₁/k₂times, and recording the data stream on the recording medium.

In one embodiment of the present invention, the data recording stepincludes the step of recording digital data indicating a value of thek₁/k₂ on the recording medium.

In another embodiment of the present invention, the data recording stepincludes the step of recording digital data indicating a value of thek₁/k₂ on an auxiliary storage medium provided in a cassetteaccommodating the recording medium.

According to another aspect of the present invention, the digital datarecording device provided with a rotary cylinder, and a head mounted onthe rotary cylinder, for recording digital data on a recording medium,comprises

recording means for recording a data stream having a predetermined datarate on the recording medium based on a recording format capable ofselecting a plurality of track angles determined in accordance with aspeed vector of the head and a speed vector of the recording medium.

In one embodiment of the present invention, the above-mentioned digitaldata recording device comprises first recording control means forcontrolling traveling of the recording medium so that the data stream isrecorded on the recording medium once in every m times scans of the headwhen the data stream has a data rate which is 1/m (m is a naturalnumber) of a predetermined data rate.

In another embodiment of the present invention, the above-mentioneddigital data recording device comprises second recording control meansfor stopping traveling of the recording medium so as not to record thedigital data on the recording medium for a predetermined period of time.

In still another embodiment of the present invention, theabove-mentioned digital data recording device comprises second recordingcontrol means for stopping traveling of the recording medium so as notto record the digital data on the recording medium for a predeterminedperiod of time.

Alternatively, the digital data recording device of the presentinvention for recording a data stream having a predetermined data rateof n bit/s (n is a positive number), comprises:

data compressing means for receiving an input data stream having a datarate of n bit/s or less and performing time axis compression withrespect to the input data stream so that the input data stream iscompressed into an output data stream having a data rate of n bit/s; and

data recording means for recording the output data stream on therecording medium.

Alternatively, the digital data recording device of the presentinvention provided with a rotary cylinder, and a head mounted on therotary cylinder, for recording digital data on a recording medium,comprises

recording means for recording a data stream at a track pitch smallerthan a track pitch at which normal-rate signals are to be recorded, in acase where the data stream is low-rate signals to be reproduced at adata rate lower than a predetermined data rate.

In one embodiment of the present invention, the recording means recordsdigital data indicating at least one of the group consisting of a trackangle during recording, a traveling speed of the recording medium, arotation number of the rotary cylinder, and a track pitch of therecording medium.

In another embodiment of the present invention, the recording meansrecords digital data indicating at least one of the group consisting ofa track angle during recording, a traveling speed of the recordingmedium, a rotation number of the rotary cylinder, and a track pitch ofthe recording medium.

According to still another aspect of the present invention, the digitaldata reproducing device for reproducing digital data from a recordingmedium by using a head mounted on a rotary cylinder, comprises:

data reproducing means for reproducing digital data recorded on therecording medium at a data rate higher than a data rate during recordingby increasing a rotation number of the rotary cylinder; and

data output means for selectively outputting required data among thereproduced digital data.

Alternatively, the digital data reproducing device of the presentinvention for reproducing digital data from a recording medium by usinga head mounted on a rotary cylinder, comprises:

data reproducing means for reproducing low-rate signals, which are to bereproduced at a data rate lower than a predetermined data rate, at adata rate higher than a data rate of the low-rate signals with therotation number of the rotary cylinder substantially equal to therotation number of the rotary cylinder during reproducing normal-ratesignals which are to be reproduced at the predetermined data rate, in acase where the low-rate signals and the normal-rate signals are present;and

data output means for selectively outputting required data among thereproduced digital data.

In one embodiment of the present invention, the data reproducing meansand the data output means reproduce the low-rate signals by using aprocessing method utilized for slow reproduction of the normal-ratesignals.

In another embodiment of the present invention, the data rate is inproportion with a traveling speed of the recording medium.

In still another embodiment of the present invention, the data rate isin proportion with a traveling speed of the recording medium.

According to still another aspect of the present invention, the digitaldata recording and reproducing device comprises recording means forrecording a data stream having a predetermined data rate on a recordingmedium by using a head mounted on a rotary cylinder and reproducingmeans for reproducing a data stream recorded by the recording means,

wherein, in a case where a data stream to be recorded is a data streamhaving a low data rate to be reproduced at a data rate lower than apredetermined data rate, the reproducing means reproduces the datastream at the predetermined data rate, and the recording means recordsthe data stream reproduced by the reproducing means at the predetermineddata rate.

In one embodiment of the present invention, the data rate is inproportion with a traveling speed of the recording medium.

In another embodiment of the present invention, the recording meansrecords digital data indicating at least one of the group consisting ofa track angle during recording, a traveling speed of the recordingmedium, a rotation number of the rotary cylinder, and a track pitch ofthe recording medium.

Alternatively, the digital data recording device of the presentinvention provided with a rotary cylinder, and a head mounted on therotary cylinder, for recording digital data on a recording medium,comprises

recording means for recording the digital data on the recording mediumso that an angle of tracks formed on the recording medium traveling at arecording medium traveling speed different from a predeterminedrecording medium traveling speed is equal to an angle of tracks formedon the recording medium traveling at the predetermined recording mediumtraveling speed.

In one embodiment of the present invention, the recording means controlsan angle formed by a rotation axis of the rotary cylinder and atraveling direction of the recording medium in accordance with therecording medium traveling speed.

In another embodiment of the present invention, the recording meansincludes head moving means for moving the head in a direction parallelwith a rotation axis of the rotary cylinder.

In still another embodiment of the present invention, the recordingmeans records data indicating the recording medium traveling speed onthe recording medium.

Thus, the invention described herein makes possible the advantages of(1) providing a recording device in which long-time recording can beperformed by converting a format; (2) providing a recording andreproducing device in which data having a data rate of a plurality ofinput data streams can be recording and reproduced; (3) providing arecording device in which the rotation number of the cylinder and thetape traveling speed during recording can be set at various kinds ofvalues by using a recording format capable of selecting a plurality oftypes of track angles; (4) providing a reproducing device in which allthe data can be reproduced even in the case where the recording trackangles are not identical; (5) providing a recording device in whichlow-rate signals are subjected to a time axis compression in order to berecorded in a short period of time at a normal data rate; (6) providinga recording device in which data can be recorded with a track pitchsmaller than standardized one; (7) providing a recording and reproducingdevice in which data is reproduced at a data rate higher than the datarate which is to be used for reproducing and the reproduced data isrecorded at the higher data rate, making it possible for high-speedcopying; and (8) providing a recording device in which even data havinga data rate other than a standard one can be appropriately recorded.

These and other advantages of the present invention will become apparentto those skilled in the art upon reading and understanding the followingdetailed description with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a recording and reproducing device ofExample 1 according to the present invention.

FIGS. 2A to 2E are block diagrams of a first recording adaptor used inExample 1 according to the present invention.

FIG. 3 is a block diagram of a first reproducing adaptor used in Example1 according to the present invention.

FIG. 4 is a block diagram of a recording and reproducing device ofExample 2 according to the present invention.

FIGS. 5A to 5D are timing diagrams showing the operation of recordingand reproducing in Example 2 according to the present invention.

FIG. 6 is a block diagram of a recording and reproducing device ofExample 3 according to the present invention.

FIGS. 7A and 7B are timing diagrams showing the operation of recordingand reproducing in Example 3 according to the present invention.

FIGS. 8A and 8B are diagrams showing a head construction of180°-opposing double heads and the positional relationship between themagnetic head and the magnetic tape in helical recording used in theexamples of the present invention, respectively.

FIGS. 9A and 9B are diagrams showing other head construction of “paired”heads used in the examples of the present invention.

FIG. 10 shows a track pattern in helical recording at normal speed.

FIG. 11 shows a track pattern in helical recording in Example 4according to the present invention.

FIG. 12 is a timing diagram in helical recording in Example 4 accordingto the present invention.

FIG. 13 is a timing diagram in helical recording under other conditionsin Example 4 according to the present invention.

FIG. 14 is a timing diagram in helical recording under other conditionsin Example 4 according to the present invention.

FIG. 15 is a diagram illustrating a track pattern of a recording deviceaccording to the present invention.

FIG. 16 is a block diagram of a reproducing device of Example 6according to the present invention.

FIG. 17 is a block diagram of a reproducing device of Example 7according to the present invention.

FIG. 18 is a block diagram of a recording device of Example 8 accordingto the present invention.

FIG. 19 is a block diagram of a recording device of Example 9 accordingto the present invention.

FIG. 20 is a block diagram of a recording and reproducing device ofExample 10 according to the present invention.

FIG. 21 is a diagram illustrating a recording device of Example 11according to the present invention.

FIG. 22 is a diagram showing the relationship between the track pitchand the tape traveling speed in Example 11 according to the presentinvention.

FIG. 23 is a block diagram of a recording device of ConstructionalExample 2 of Example 11 according to the present invention.

FIGS. 24A to 24D are timing diagrams showing the operation of recordingin Constructional Example 2 of Example 11 according to the presentinvention.

FIG. 25 is a block diagram of a recording device of ConstructionalExample 3 of Example 11 according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The entire disclosure of U.S. patent application Ser. No. 08/893,612filed on Jul. 10, 1997, now U.S. Pat. No. 6,147,823, is expresslyincorporated by reference herein.

Hereinafter, the present invention will be described by way ofillustrative examples with reference the drawings. The identicalreference numerals denote the identical components.

EXAMPLE 1

FIG. 1 is a block diagram of a recording and reproducing device ofExample 1 according to the present invention. In this figure, a videoA/D converter 11, a video signal coding processor 12, an audio A/Dconverter 13, an audio signal coding processor 14, an error correctionencoder 15, a modulator 16, a magnetic recording and reproducing system17, a demodulator 18, an error correction decoder 19, a video signaldecoding processor 20, a video D/A converter 21, an audio signaldecoding processor 22, and an audio D/A converter 23 are the same asthose used in conventional DVCRS; therefore, the detailed descriptionthereof will be omitted.

In the present example, an input selector 31 is provided between theerror correction encoder 15, and the video signal coding processor 12and the audio signal coding processor 14. The input selector 31 selectsbetween the outputs (terminals V and A) of the coding processors 12 and14 and the outputs (terminals v and a) of a first recording adaptor 32.The outputs selected by the input selector 31 are input to the errorcorrection encoder 15. The input selector 31 is a type of an inputselector and can be switched automatically or manually. The firstrecording adaptor 32 receives a plurality of signals having a data ratelower than that of ordinary video and audio signals. Then, the firstrecording adaptor 32 converts the signals thus received into the sameformat as that of the outputs of the video signal coding processor 12and the outputs of the audio signal coding processor 14, and output theconverted signals to the input selector 31. In the specification, “rate”refers to data rate. Furthermore, “data rate of input data stream”refers to data rate of digital data input to the first recording adaptor32, and “recording rate” refers to the data rate of digital data inputto the modulator 16. The other construction on the recording side is thesame as that of the conventional example.

On the reproducing side, the output of the error correction decoder 19is input to the video signal decoding processor 20, the audio signaldecoding processor 22, and a first reproducing adaptor 33 The firstreproducing adaptor 33 reversely converts the format of the signal thusreceived and divides the signal into the original signals.

An example of the first recording adaptor 32 is shown in FIG. 2A. Thefirst recording adaptor 32 is designed so as to receive 4 low-ratesignals. Here, it is assumed that the total of the data rates of thesesignals does not exceed a maximum recording data rate (hereinafter,referred to as maximum data rate) of n bit/s (n is a positive number) ofthe recording and reproducing device. An input selector 34 switchesthese inputs. FIG. 2B shows the connection in the case where foursignals are input; FIG. 2C shows the connection in the case where threesignals are input; FIG. 2D shows the connection in the case where twosignals are input; and FIG. 2E shows the connection in the case whereone signal is input. These four outputs are input into a formatconverter 35. The format converter 35 converts the data thus receivedinto the same format as that of the output of the video signal codingprocessor 12 and the output of the audio signal coding processor 14.Here, in the case where all of the low-rate signals have a data ratesmaller than ¼ of the maximum data rate of the recording and reproducingdevice, data corresponding to the data rate difference can be added. Forexample, the format converter 35 performs various processings such asthe addition of a fixed value, the addition of an error correction code,and the multiple-writing by selecting important information. In the casewhere such a variety of signals are recorded, it is required to knowcertain information (hereinafter, referred to as auxiliary data) such asthe data rate of signals, the number of signals, and the format ofsignals (how the signals are formatted by the format converter 35) atthe time of reproducing data. Thus, these auxiliary data are required tobe recorded on the magnetic tape, and added to the video data and audiodata.

FIG. 3 is a block diagram of the first reproducing adaptor 33. Theoutput of the error correction decoder 19 is input to a formatreverse-converter 36. The format reverse-converter 36 judges the signalformat based on the auxiliary data and converts the output of the errorcorrection decoder 19 into the format of low-rate signals. The output ofthe format reverse-converter 36 is input to input terminals 37 a to 37 dof a quad 1-4 demultiplexer 37 composed of four 1-4 demultiplexers. Thequad 1-4 demultiplexer 37 outputs four signals respectively to outputterminals 37-1 a to 37-1 d, 37-2 a to 37-2 d, 37-3 a to 37-3 d, and 37-4a to 37-4 d in accordance with selection signals. Four outputs 37-1 a to37-1 d of the demultiplexer 37 are directly input to input terminals38-1 a to 38-1 d of a quad 4-1 multiplexer 38. The output terminals 37-2a and 37-2 d are directly connected to input terminals 38-2 a and 38-2 dof the quad 4-1 multiplexer 38, and the output terminals 37-2 b and 37-2c are connected to an input terminal 38-2 b of the quad 4-1 multiplexer38 through a 2-input selector 39. An input terminal 38-2 c is kept open.The output terminals 37-3 a, 37-3 b and 37-3 c, 37-3 d are respectivelyconnected to input terminal 38-3 a and 38-3 c of the quad 4-1multiplexer 38 through 2-input selectors 39. Input terminals 38-3 b and38-3 d are kept open. The output terminals 37-4 a to 37-4 d areconnected to an input terminal 38-4 a of the quad 4-1 multiplexer 38through a 4-input selector 40. Input terminals 38-4 b to 38-4 d are keptopen. The quad 4-1 multiplexer 38 selects one group of input terminalsamong the input terminals 38-1 a to 38-1 d; the input terminals 38-2 ato 38-2 d; the input terminals 38-3 a to 38-3 d; and the input terminals38-4 a to 38-4 d. In the case where the input terminals 38-1 a to 38-1 dare selected, the input terminal 38-1 a is connected to an outputterminal 38 a, the input terminal 38-1 b is connected to an outputterminal 38 b, the input terminal 38-1 c is connected to an outputterminal 38 c, and the input terminal 38-1 d is connected to an outputterminal 38 d. Signals which are multiple-recorded by the 2-inputselector 39 and the 4-input selector 40 are selected corresponding tothe number of output signals, whereby signals having errors are removed.Regarding a plurality of output signals, only one of them may be used,or in the case where recorded signals are video signals,picture-in-picture signals, multi-screen signals, etc., some of them maybe simultaneously used.

According to the above-mentioned construction, a number of types ofsignals can be simultaneously recorded or signals of one kind aremultiple-recorded by the same recording and reproducing device withoutchanging the format of the tracks. If the multiple-recording is madepossible, the error correction ability can be enhanced; therefore,inexpensive magnetic tape of low quality can be utilized as a recordingmedium. Alternatively, by decreasing the track pitch (i.e., lowering thetape traveling speed), long-time recording can be performed.

It is noted that the recording and reproducing device of the presentexample having another construction provide the same effects. In thepresent example, the number of low-rate signals is 4; however, anynumber of low-rate signals enables the similar recording and reproducingof data. These signals may not be the same. Furthermore, these signalsmay have the same or different data rates.

The recording adaptor 32 and the reproducing adaptor 33 may be providedoutside of the recording and reproducing device or may be built therein.In the case where the recording adaptor 32 and the reproducing adaptor33 are built in the recording and reproducing device, the functionsthereof can be contained in the error correction encoder 15 and theerror correction decoder 19. In the case where the recording adaptor 32and the reproducing adaptor 33 are externally provided, signals havingdifferent data rates or different data formats can be recorded bychanging the recording adaptor 32 and the reproducing adaptor 33.

In the recording and reproducing device performing no high efficiencycoding of input signals, the input selector 31 can be provided beforethe video signal coding processor 12 and the audio signal codingprocessor 14, not right before the error correction encoder 15. Thisenables the use of a shuffling function of the video signal codingprocessor 12 and the audio signal coding processor 14.

In the present example, auxiliary data such as the data rate of signals,the number of signals, and the kinds of formats is recorded on themagnetic tape simultaneously with the recording of audio and video data.In the case where the magnetic tape is accommodated in a cassette, thecassette can be attached to a secondary storage medium (for example, anIC memory and a sheet having magnetic stripes), and the auxiliary datacan be recorded in the secondary storage medium. Thus, the auxiliarydata can be obtained before starting the reproducing operation.Alternatively, the auxiliary data can be input to the recording andreproducing device from outside every time data is reproduced.

EXAMPLE 2

FIG. 4 is a block diagram of a recording and reproducing device ofExample 2 according to the present invention. A video A/D converter 11,a video signal coding processor 12, an audio A/D converter 13, an audiosignal coding processor 14, a video signal decoding processor 20, avideo D/A converter 21, an audio signal decoding processor 22, an audioD/A converter 23, and an input selector 31 are the same as those ofExample 1. The output of the input selector 31 is input to a recordingand reproducing selector 43 through an error correction encoder 41 and amodulator 42. The recording and reproducing selector 43 selects an inputor an output at the time of recording and reproducing data. The outputsof the recording and reproducing selector 43 are connected to a rotaryhead of a magnetic recording and reproducing system 44. When low-ratesignals are input, a tape speed of the magnetic recording andreproducing system 44 is switched by a tape traveling controller 45 inaccordance with the data rate of input signals.

In the present example, the low-rate signals are input to a secondrecording adaptor 46. The second recording adaptor 46 converts the inputsignals into a format which is similar to that of the output signals ofthe video signal coding processor 12 and the audio signal codingprocessor 14 which corresponds to the recording data rate. At the sametime, the data rate of the low-rate signals is output to the errorcorrection encoder 41, the modulator 42, and the tape travelingcontroller 45 as tape traveling speed data. Output terminals of therecording and reproducing selector 43 are connected to a demodulator 47and an error correction decoder 48. The outputs of the error correctiondecoder 48 are given to the video signal decoding processor 20, theaudio signal decoding processor 22, and a second reproducing adaptor 49.The error correction decoder 48 performs error correction and decodingof the received data, and reads the tape traveling speed datasimultaneously recorded on the magnetic tape. Based on the tapetraveling speed data, the demodulator 47 and the second reproducingadaptor 49 are operated and the tape traveling speed of the tapetraveling controller 45 is controlled.

FIGS. 8A and 8B are diagrams schematically showing the rotary head ofthe magnetic recording and reproducing system 44. The magnetic recordingand reproducing system 44 reproduces data from and records data on themagnetic tape, using the rotary head by a helical scanning method. Here,a double-azimuth head is used as the rotary head. This double-azimuthhead includes two heads provided at the periphery of a cylinder so thata straight line can be obtained by connecting the positions of the twoheads to a center axis of the cylinder (hereinafter, such two heads arereferred to as 180°-opposing double heads). In this case, the magnetictape is wrapped around a rotary cylinder by 180°. It is assumed that thehead having one azimuth angle is the A head and the head having theother azimuth angle is B head.

Hereinafter, the operation of the present example will be described. Inthe case where the error correction encoder 41 is connected to terminalsV and A of the input selector 31, the recording and reproducing deviceof the present example records and reproduces video signals and audiosignals in the same manner as in the conventional example. In the casewhere the error correction encoder 41 is connected to terminals v and a,the second recording adaptor 46 outputs the data rate of signalstransmitted at a low data rate as tape traveling speed data. When thedata rate of the low-rate signals is 1/j or less (j is an odd number) ofthe maximum data rate of the recording and reproducing device, the tapetraveling speed is 1/j of conventional tape traveling speed.

FIGS. 5A to 5D are timing diagrams in which the period for actuallyrecording and reproducing data by each head is represented as “High” andthe period for recording and reproducing no data by each head isrepresented as “Low”. FIG. 5A is a timing diagram in the case of theconventional recording and reproducing. FIGS. 5B, 5C, and 5D are timingdiagrams in the case where j is 3, 5, and 7, respectively. A recordingmethod, in which irrespective of the fact that the magnetic head isscanning, data is recorded only once in every n times scans, is referredto as “skip” recording. The use of the 180°-opposing double headsrequires the condition that j is an odd number. In order to alternatelyscan by using 180°-opposing double heads with a different azimuth,scanning must be performed in the following manner: A(BA)B(AB)A(BA) . .. , where A denotes a head having one azimuthal angle and B denotes ahead having another azimuthal angle, and the parentheses correspond to ahead performing no recording and reproducing. Since scanning withoutrecording and reproducing is performed for an even-number of times perscan, j results in an odd number.

The error correction encoder 41, the modulator 42, the magneticrecording and reproducing system 44, the demodulator 47, and the errorcorrection decoder 48 respectively function in the same manner as in theerror correction encoder 15, the modulator 16, the magnetic recordingand reproducing system 17, the demodulator 18, and the error correctiondecoder 19, except for the functions enabling the operationcorresponding to the above-mentioned skip recording and reproducing.Furthermore, the recording and reproducing selector 43 connects the headto the modulator 42 in the case of recording data, and connects the headto the demodulator 45 in the case of reproducing data.

The input data stream at a low data rate are converted into a formatwhich is the same as that of the outputs of the video signal codingprocessor 12 and the audio signal coding processor 14 and whichcorresponds to the maximum data rate. Thereafter, the consignals aresubjected to error correction coding and modulation. At the time ofreproducing data, the data is demodulated by the demodulator 47 andsubjected to error correction and decoding by the error correctiondecoder 48. Thereafter, the data is reverse-converted into a format ofthe low-rate signals by the second reproducing adaptor 49, and thus,recorded signals are reproduced.

In the case where the data rate of the low-rate signals is smaller than1/j (j>1) of the maximum data rate of the recording and reproducingdevice, the second recording adaptor 46 can add data corresponding tothe data rate difference. For example, the second recording adaptor 46performs processings such as the addition of a fixed value, the additionof error correction coding, and the multiple-writing by selectingimportant information. In the case where such a variety of signals arerecorded, it is required to know the auxiliary data at the time ofreproducing data. Thus, the auxiliary data must be recorded on themagnetic tape. The auxiliary data is recorded on the magnetic tape afterbeing added to video data and audio data by the format converter (notshown) in the second recording adaptor 46. At the time of reproducingdata, since the tape traveling speed data is obtained by the errorcorrection decoder 48, it is possible to reproduce data at anappropriate tape traveling speed. When the tape traveling speed isvaried, track angles of tracks to be formed (an angle formed by a tapeedge and each track) are slightly different. However, this does notcause any problems for obtaining the tape traveling speed data.

According to the above-mentioned construction, the format of the tracksis not changed. Thus, a long-time recording which is j times that of thelow-rate signals can be performed only by changing the tape travelingspeed and the recording timing, using the same recording and reproducingdevice. Furthermore, when j is j₁×j₂, j₂ times long-time recording canbe performed by conducting j₁ times multiple-recording. Whenmultiple-recording can be performed, error correction ability isenhanced. Consequently, an inexpensive magnetic tape of poor quality canbe used. In addition, a long-time recording is made possible bydecreasing the track pitch (that is, lowering the tape traveling speed).In the case where the head width is larger than the track pitch, eventhough multiple-recording is not performed, an inexpensive magnetic tapeof poor quality can be used by increasing the track pitch (that is,multiplying the tape traveling speed by a head width/normal track pitch)so as to reduce the generation of errors.

The block construction of the recording and reproducing device of thepresent example is merely one example. The same effects can also beobtained with any construction. In the present example, thedouble-azimuth 180°-opposing double heads (the magnetic tape is wrappedaround the rotary cylinder by 180°) as shown in FIGS. 8A and 8B is used.This limits the value of j to odd numbers. If “paired” heads shown inFIGS. 9A and 9B are used, i.e., the head A and the head B are disposedadjacent to each other, j can be any number of 1 or more. Alternatively,in the case where data is recorded by providing a guard band instead ofusing the azimuth, j is any number of 1 or more irrespective of the headconstruction.

In the present example, the recording and reproducing timing as shown inFIGS. 5A to 5D is used. For example, in the case where a head utilizinga piezoelectric element is used, the same track can be repeatedlyreproduced even at timings other than this timing, and error correctionability can be enhanced.

Furthermore, the recording adaptor 46 and the reproducing adaptor 49 canbe provided outside of the recording and reproducing device or builttherein. In the case where the recording adaptor 46 and the reproducingadaptor 49 are built in the recording and reproducing device, thefunctions thereof can be contained in the error correction encoder 41and the error correction decoder 48. In the case where the recordingadaptor 46 and the reproducing adaptor 49 are externally provided,signals having different data rates are recorded by changing therecording adaptor 46 and the reproducing adaptor 49.

In the recording and reproducing device performing no high efficiencycoding of input signals, the input selector 31 can be provided beforethe video signal coding processor 12 and the audio signal codingprocessor 14, not immediately before the error correction encoder 41.This enables the use of a shuffling function of the video signal codingprocessor 12 and the audio signal coding processor 14.

In the present example, the tape traveling speed data is also recordedon the magnetic tape simultaneously with the recording of audio andvideo data. In the case where the magnetic tape is accommodated in acassette, the cassette can be attached to a secondary storage medium(for example, an IC memory and a sheet having magnetic stripes), and thetape traveling speed data can be recorded in the secondary storagemedium. Thus, the appropriate tape traveling speed data can be obtainedbefore starting the reproducing operation. Alternatively, theappropriate tape traveling speed data can be input to the recording andreproducing device from outside every time data is reproduced.

EXAMPLE 3

FIG. 6 is a block diagram of a recording and reproducing device ofExample 3 according to the present invention. A video A/D converter 11,a video signal coding processor 12, an audio A/D converter 13, an audiosignal coding processor 14, a video signal decoding processor 20, avideo D/A converter 21, an audio signal coding processor 22, an audioD/A converter 23, an input selector 31, and a recording and reproducingselector 43 are the same as those of Example 2. The detailed descriptionthereof will be omitted.

Output terminals of the input selector 31 are connected to an errorcorrection encoder 51 and a modulator 52, and a modulated output of themodulator 52 is given to the recording and reproducing selector 43. Inthe present example, low-rate input signals are given to a thirdrecording adaptor 53. The third recording adaptor 53 converts the giveninput signals into a format which is the same as that of the outputs ofthe video signal coding processor 12 and the audio signal codingprocessor 14 and which corresponds to the recording rate. The outputs ofthe third recording adaptor 53 are given to terminals v and a of theinput selector 31. The data rate of low rate signals input to the thirdrecording adaptor 53 is given as recording operation data, to the errorcorrection encoder 51, the modulator 52, a tape traveling controller 54,a rotary cylinder driving control device 55, and an operation clockselector 56. The operation clock selector 56 supplies the operationclock corresponding to the recording rate at the time of recording data.The tape traveling controller 54 and the rotary cylinder driving controldevice 55 controls the tape traveling speed and the rotation speed ofthe rotary cylinder of the magnetic recording and reproducing system 57,respectively, based on recording operation data. Here, the recordingoperation data is one type of auxiliary data, which is data fordetermining the tape traveling speed and the rotation speed of therotary cylinder of the magnetic recording and reproducing system 57. Atthe time of reading data, the recording and reproducing selector 43 isswitched to a demodulator 58 side. The demodulator 58 demodulates thesignals recorded on the magnetic tape and generates an operation clock.An error correction decoder 59 performs error correction to decode theoriginal signals and read video data and audio data. At this time, therecording operation data recorded on the magnetic tape is read so as tobe given to the demodulator 58, a third reproducing adaptor 60, the tapetraveling controller 54, and the rotary cylinder driving control device55, whereby the tape speed at the time of reproducing data iscontrolled. The third reproducing adaptor 60 reproduces and outputsoriginal low-rate signals based on this recording operation data.

In the present example, the magnetic recording and reproducing system 57has a rotary head as shown in FIGS. 8A and 8B and records data on themagnetic tape by a helical scanning method. For example, adouble-azimuth 180°-opposing double heads is used as the rotary head.Here, the magnetic tape is wrapped around a cylinder by 180°. It isassumed that the head with one azimuth angle is A head and the head withthe other azimuth angle is B head.

Hereinafter, the operation of the present example will be described. Inthe present example, video signals and audio signals are recorded andreproduced at a normal speed in the same manner as in conventionalDVCRs, in the case where the error correction encoder 51 is connected toterminals V and A by the input selector 31.

In the case where the error correction encoder 51 is connected toterminals v and a, the data rates of low-rate signals are output fromthe third recording adaptor 53 as recording operation data. When thetotal of the data rates of the low-rate signals is k₁/k₂ or less (k₁, k₂are integers, k₁<k₂) of the maximum data rate (n bit/s, where n is apositive number) of the recording and reproducing device, the data rateat which data is recorded on the magnetic tape is made k₁/k₂ ofconventional data rate. At the same time, the rotation number of thecylinder and the tape traveling speed are made k₁/k₂ of the conventionalrotation number and the conventional tape traveling speed, respectively.

FIGS. 7A and 7B are timing diagrams in which the period for actuallyrecording and reproducing data by each head is represented as “High” andthe period for recording and reproducing no data by each head isrepresented as “Low”. FIG. 7A is a timing diagram in the case of theconventional recording and reproducing. FIG. 7B is a timing diagram inthe case of k₁/k₂=⅘. Eight tracks are formed according to the timingdiagram of FIG. 7B within a period of time during which 10 tracks areformed according to the timing diagram of FIG. 7A. The period of timerequired for forming one track shown in the timing diagram of FIG. 7B is{fraction (5/4)} times that shown in the timing diagram of FIG. 7A;however, the recording rate shown in the timing diagram of FIG. 7B is ⅘times that shown in the timing diagram of FIG. 7A. Therefore, the amountof data recorded at ⅘ of the normal rate in one track is the same asthat recorded at normal rates. Consequently, input data stream having adata rate of ⅘ of normal data rate can be recorded for {fraction (5/4)}times of maximum recording time. Thus, a long-time recording of alow-rate signal is possible.

The error correction encoder 51, the modulator 52, the magneticrecording and reproducing system 57, the demodulator 58, and the errorcorrection decoder 59 are provided with additional functions to operatefor recording and reproducing utilizing variable rotation number andvariable tape traveling speed. Except for these functions, the errorcorrection encoder 51, the modulator 52, the magnetic recording andreproducing system 57, the demodulator 58, and the error correctiondecoder 59 are respectively the same as the error correction encoder 15,the modulator 16, the magnetic recording and reproducing system 17, thedemodulator 18, and the error correction decoder 19. The operation clockselector 56 supplies the operation clock corresponding to the recordingrate to the error correction encoder 51 and the modulator 52 at the timeof recording data. At the time of reproducing data, the operation clockdemodulated from signals reproduced from the magnetic tape is suppliedto the demodulator 58 and the error correction decoder 59.

The third recording adaptor 53 converts the low-rate signals into aformat which is the same as that of the outputs of the video signalcoding processor 12 and the audio signal coding processor 14 and whichcorresponds to the recording rate. After being subjected to the errorcorrection coding and modulation, the signals are recorded. At the timeof reproducing data, after being subjected to demodulation and errorcorrection decoding, the data is reverse-converted into low-rate signalsby the third reproducing adaptor 60, whereby the recorded signals can beobtained.

In the case where the data rate of the low-rate signals is smaller thank₁/k₂ of the maximum data rate of the recording and reproducing device,the third recording adaptor 53 adds data corresponding to the data ratedifference. For example, the third recording adaptor 53 performsprocessings such as the addition of a fixed value, the addition of errorcorrection coding, and multiple-writing by selecting importantinformation.

When the signals are recorded or reproduced by the above-mentionedmethod, there is a need to know the auxiliary data. For this reason, theauxiliary data should be recorded on the magnetic tape. The auxiliarydata to be added to video and audio data is also output from the thirdrecording adaptor 53. At the time of reproducing data, since therecording operation data is obtained by the error correction decoder 59,correct reproduction is made possible.

According to the above-mentioned construction, the format of tracks isnot changed. Thus, long-time recording, i.e., k₂/k₁ times longerrecording, can be performed with respect to low-rate signals merely bychanging the recording operation, using the conventional recording andreproducing device. Furthermore, the generation of errors can be reducedby recording data with a wider track pitch (i.e., increasing tape thetape traveling speed), using the head with larger width. As a result, aninexpensive magnetic tape of poor quality can be utilized.

The block construction of the recording and reproducing device of thepresent example is merely an example.

In the present example, the double-azimuth 180°-opposing double heads asshown in FIGS. 8A and 8B is used. Head A and head B are located in sucha manner that head A and head B are symmetric with respect to a rotationaxis of a rotary cylinder. In this case, the magnetic tape is wrappedaround a cylinder by 180°.

In the present example, the operation clock selector 56 supplies theoperation clock corresponding to the recording data rate to the errorcorrection encoder 51 and the modulator 52. Since signals correspondingto a desired recording data rate are input to the modulator 52, a signalprocessing such as forming blanks between data can be performed insteadof changing the operation clock. In the case where the operation clockis not changed, the constructions of the error correction encoder 51 andthe modulator 52 are not required to be changed.

The third recording adaptor 53 and the third reproducing adaptor 60 maybe provided outside of the recording and reproducing device or may bebuilt therein. In the case where the third recording adaptor 53 and thethird reproducing adaptor 60 are built in the recording and reproducingdevice, the functions thereof can be contained in the error correctionencoder 51 and the error correction decoder 59. In the case where thethird recording adaptor 53 and the third reproducing adaptor 60 areexternally provided, signals having different data rates can be recordedby changing the third recording adaptor 53 and the third reproducingadaptor 60.

In the recording and reproducing device performing no high efficiencycoding of input signals, the input selector 31 can be provided beforethe video signal coding processor 12 and the audio signal codingprocessor 14, not right before the error correction encoder 51. Thisenables the use of a shuffling function of the video signal codingprocessor 12 and the audio signal coding processor 14.

In the present example, the recording operation data is also recorded onthe magnetic tape simultaneously with the recording of audio and videodata. In the case where the magnetic tape is accommodated in a cassette,the cassette can be attached to a secondary storage medium (for example,an IC memory and a sheet having magnetic stripes), and the recordingoperation data can be recorded in the secondary storage medium. Thus,the appropriate recording operation data can be obtained before startingthe reproducing operation. Alternatively, the appropriate recordingoperation data can be input to the recording and reproducing device fromoutside every time data is reproduced.

EXAMPLE 4

Hereinafter, the long-time recording of low-rate signals in a recordingdevice of Example 4 according to the present invention will bedescribed. In the present example, the tape traveling speed of thesecond and third examples is modified. The present example will bedescribed with reference to FIG. 6. In the case where the errorcorrection encoder 51 is connected to the terminals V and A by the inputselector 31, video signals and audio signals are recorded and reproducedat a normal speed in the same manner as in conventional DVCRs. When datais recorded at a normal speed, the traveling speed of a magnetic tape isset to be 18 mm/s by the tape traveling controller 54. In an auxiliarydata storage region of the magnetic tape, the value of data rate 24Mbit/s at input data stream is recorded. FIG. 10 is a diagram showing atrack pattern during recording at a normal speed.

In the case where the error correction encoder is connected to theterminals v and a, the data rate of low-rate signals is output asrecording operation data from the third recording adaptor 53.

Hereinafter, the operation of recording and reproducing data will bedescribed, in the case where the data rate of input video signals is 4Mbit/s, i.e., the data rate is ⅙ of a 24 Mbit/s normal data rate.

Recording operation data indicating that the data rate at the input datastream is 4 Mbit/s is input to the operation clock selector 56. Acommand is input to the tape traveling controller 54 so that the tapetraveling speed becomes ⅓ of that in the case of data rate of 24 Mbit/s,that is, 6 mm/s. The output signal of the operation clock selector 56controls the recording and reproducing selector 43 so that data isrecorded on the magnetic tape during only one scan out of three scans ofthe magnetic tape by the recording and reproducing head and data is notrecorded during the remaining two scans. In stead of controlling therecording and reproducing selector 43, controlling the error correctionencoder 51 can be used for the above mentioned skip recording. Assumingthat the head path of the nth rotation by head A is represented by Anand the head path of the nth rotation by head B is represented by Bn,data is recorded when the head paths represented by An, Bn+1, An+3, andBn+4 trace the magnetic tape, and data is not recorded when the headpaths represented by Bn, An+1, An+2, Bn+2, Bn+3, and An+4 trace themagnetic tape, as shown in FIG. 11. FIG. 12 is a timing diagram duringskip recording. Here T_(α) represents a time required for the cylinderto rotate by one turn when the tape traveling speed is 6 mm/s; and T_(β)represents a time required for the cylinder to rotate by three turnswhen the tape traveling speed is 18 mm/s. A solid line represents aperiod during which data is recorded, and a broken line represents aperiod during which data is not recorded.

In the present example, the tape traveling speed which is one over anodd number (e.g. ⅓) of the normal tape traveling speed is used, and skiprecording is performed once in every certain odd number times (e.g.,once in every three times). The reason for this is as follows:

In the case where the recording and reproducing head used in the presentexample in a 180°-opposing double heads as shown in FIGS. 8A and 8B,when the tape traveling speed which is one over an even number (e.g., ½)is used, and skip recording is performed once in every certain evennumber times (e.g., once in every four times), only data traced by onehead path of the head A and the head B is reproduced. As a result, onlyrecording using one kind of azimuth is realized.

FIG. 13 is a timing diagram showing intermittent recording in which thetraveling of the magnetic tape is stopped after skip recording. In FIG.13, the solid line represents a period during which data is actuallyrecorded on the magnetic tape in skip recording; and the broken linerepresents a period during which data is not recorded in skip recordingand a period during which data is not recorded by stopping the travelingof the magnetic tape. The period tp is a period during which themagnetic tape travels, and the period tq is a period during which datais not recorded by stopping the traveling of the magnetic tape. Thecontrols such as the skip recording for a predetermined period of timeand the stop of the traveling of the magnetic tape for a predeterminedperiod of time are performed based on the recording operation data. Inthe present specification, intermittent recording means a recordingmethod in which two modes are alternately executed: Two modes are arecording mode in which the tape travels and data is recorded and anon-recording mode in which the tape does not travel and data is notrecorded in the present example, the periods tp and tq shown in FIG. 13satisfy the following Equation (1):

tp=tq=t 1  (1)

As in the present example, in the case where signals with a 4 Mbit/sdata rate of input data stream is recorded by a recording device with arecording data rate of 24 Mbit/s, the signals are subjected to ⅙ timeaxis compression.

According to the above-mentioned recording method, signals with a 4Mbit/s data rate of input data stream which is ⅙ of a normal data rateof 24 Mbit/s can be recorded. That is, as shown in the followingEquation (2), such recording can be performed by combining the change intape traveling speed, skip recording, and intermittent recording.

⅙=(⅓)×{t 1/(t 1+t 1)}  (2)

At this time, the value of 4 Mbit/s data rate of input data stream isrecorded in an auxiliary data storage region of the magnetic tape.

Skip recording, in which the tape traveling speed is set to be 1/d of anormal data rate of input data stream, data is recorded on the magnetictape during only one scan among d times scans, and data is not recordedduring the remaining (d−1) times scans, is performed for the period oftp. Intermittent recording, in which the traveling of the magnetic tapeis stopped, is performed for the period of tq. In this case, therecording data rate becomes 1/j of the normal recording data rate, asshown in the following Equation (3):

1/j=(1/d)×{tp/(tp+tq)}  (3)

As described above, in the case where the recording and reproducingheads are 180°-opposing double heads as shown in FIGS. 8A and 8B, d isrequired to be an odd number for arranging the tracks on the magnetictape in the same manner as in the case of a normal speed shown in FIG.10. On the other hand, in the case where the recording and reproducingheads are paired heads shown in FIGS. 9A and 9B, d is not required to bean odd number.

Hereinafter, the operation of reproducing data recorded on the magnetictape will be described.

During reproducing data, the data is subjected to demodulation and errorcorrection decoding, and then, reverse-converted into a format oflow-rate signals by the third reproducing adaptor 60, whereby recordedsignals can be obtained. When the data rate of the low-rate signals issmaller than k₁/k₂ of the maximum data rate of the recording andreproducing device, the third recording adaptor 53 adds datacorresponding to the data rate difference. For example, the thirdrecording adaptor 53 performs processings such as the addition of afixed value, the addition of error correction coding, andmultiple-writing by selecting important information.

Information as to whether the transmitting data rate recorded in theauxiliary data storage region of the magnetic tape is a normal data rateof 24 Mbit/s or not is obtained by the error correction decoder 59. Whenthe transmitting data rate of recorded data is a normal data rate of 24Mbit/s, the error correction decoder 59 corrects errors of reproduceddata and outputs it.

When the recorded data rate of the input data stream is decoded to be 4Mbit/s, a command is given to the tape traveling controller 54 based onthe recording operation data obtained by the error correction decoder 59so that the tape traveling speed becomes ⅓ of the transmitting data rateof 24 Mbit/s, i.e., 6 mm/s.

The recording and reproducing selector 43 is controlled so that data isreproduced from the magnetic tape during only one scan of the magnetictape by the recording and reproducing head among three times scans, anddata is not reproduced during the remaining two scans (i.e., skipreproducing is performed).

A command for performing idle reproducing for a period of tp=t1 and forstopping the traveling of the magnetic tape during a period of tq=t1 isgiven to the tape traveling controller 54 based on the recordingoperation data.

The recording and reproducing of the signals with a data rate of 4Mbit/s which is ⅙ of a normal data rate of 24 Mbit/s have been describedabove. In this case, the data rate is made ⅙ as represented by Equation(2) by combining the change in tape traveling speed, skip recording, andintermittent recording. However, the present example is not limitedthereto. For example, in order to record the signals with a data rate of12 Mbit/s which is ½ of a normal data rate of 24 Mbit/s, data may berecorded at a normal data rate for a period of tp=t1 and the travelingof the magnetic tape is stopped for a period of tq=t1 as shown in thefollowing Equation (4):

½=t 1/(t 1+t 1)  (4)

FIG. 14 is a timing diagram in the case where data is recorded at a datarate which is ½ of a normal data rate. In FIG. 14, the solid line in aperiod of tq represents a period during which data is not recorded bystopping the traveling of the magnetic tape.

Data can be recorded at a data rate which is ⅓ of a normal data rate(i.e., 8 Mbit/s) as follows:

A command is given to the recording and reproducing selector 43 so thatdata is recorded during only one scan among three times scans of themagnetic tape by the recording head and data is not recorded during theremaining two scans. Since data can be recorded at a data rate which is⅓ of a normal data rate, intermittent transmission is not performed. Atiming diagram for recording data at a data rate which is ⅓ of a normaldata rate (i.e., 8 Mbit/s) is identical with that for skip recording inwhich data is recorded at a data rate which is ⅙ of a normal data rate(FIG. 12).

For recording data at a data rate which is {fraction (1/12)} of a normaldata rate (i.e., 2 Mbit/s), skip recording is performed for a period oftp=t1 and then the traveling of the magnetic tape is stopped for aperiod of tq=t1×3.

{fraction (1/12)}=(⅓)×{t 1/(t 1+t 1×3)}  (5)

In the past, one kind of recording and reproducing device has beenrequired for signals with each kind of data rate of input data stream.In the present example, signals with a plurality of transmitting datarates can be recorded and reproduced by one kind of recording andreproducing device by combining the change in tape traveling speed, skiprecording, and intermittent recording.

In the present example, a normal data rate of input data stream is setto be 24 Mbit/s, the transmitting speed of the magnetic tape is 8 mm/s,and the number of rotation of the cylinder is set to be 9000 rpm(rotation per minute). However, a normal data rate of input data stream,the transmitting speed of the magnetic tape, and the number of rotationof the cylinder can be arbitrarily set. For example, in Equation (3), ifd=1 and tq=0, then j=1. This parameter setting enables the conventionalrecording.

Here, data of the input data stream such as 24 Mbit/s, 4 Mbit/s, etc. isrecorded in the auxiliary data storage region of the magnetic tape.Recording data rate may be recorded instead of data rate of input datastream. The ratio of data rate of input data stream to a normalrecording data rate (e.g., ⅙ in the case where the normal data rate ofinput data stream is 24 Mbit/s and the data rate of input data stream is4 Mbit/s) may be recorded. A signal indicating whether video signals aretransmitted at a normal data rate of input data stream or at the otherdata rates may be recorded. The data rate of input data stream may berecorded in an auxiliary data storage region of the magnetic tape or maybe recorded in an auxiliary storage medium such as a memory provided ina cassette accommodating the magnetic tape. The auxiliary data storageregion refers to a region other than those of the magnetic tape in whichvideo data and audio data are recorded.

In the second, third, and fourth examples, the recording devices, inwhich video signals are recorded at two kinds of data rates, i.e., anormal data rate and a data rate lower than the normal data rate, aredescribed.

In the rotary cylinder driving control device 55 shown in FIG. 6, twooperations can be performed: a method for rotating the cylinder at thesame speed as that used for recording at a normal data rate (method A)and a method for decreasing the rotation speed of the cylinder inaccordance with the decrease in data rate (method B). According to themethod A, since the magnetic head scans the magnetic tape at three timesthe number of tracks required for recording data, data is actuallyrecorded during only one scan among three scans. Assuming that theeffective number of scans is an average value of the number of headsactually used for recording while the cylinder rotates by one turn, inthe method A, the number of scans becomes ⅓ of the number of scans atthe time when data is recorded at a normal data rate. In both of themethods A and B, the tape speed is ⅓ of that at a normal rate.

FIG. 15 shows a track pattern on the magnetic tape according to themethods A and B. The track pattern according to the method B isrepresented by a track 152, which is the identical pattern with that ofthe standard tracks. The track pattern according to the method A isrepresented by track 154. As shown in FIG. 15, the cylinder rotationspeeds are different depending upon the two methods, the respectivetrack angles are different from each other. Since it is difficult forordinary reproducing devices to deal with two kinds of track angles, therecording format is limited to either one of the track angles (i.e.,method A or method B).

According to the method A, even though data is recorded at a low datarate of 8 Mbit/s, the cylinder rotation speed is the same as that forrecording at a normal data rate. Because of this, the power consumptionand signal processing speed are the same as those for recording at anormal data rate. On the other hand, according to the method B, theratio of the cylinder rotation speed to the recording data rate duringrecording at a normal data rate becomes three times the ratio of thecylinder rotation speed to the recording data rate during recording at alow data rate. For this reason, the device having a circuit and head fora normal rate cannot be compatible with the device having a circuit andhead for ⅓ rate of the normal rate.

EXAMPLE 5

As described above, the limitation of the angle of the tracks leads tothe great limitation of devices to be actually used. For this reason, inthe present example, a data format of recording medium which permits aplurality of track angles can be used. For example, difference betweenan center line of the standard track 152 and an center line of the track154 is on the order of 3 μm at an edge of the tape, whereas the trackpitch is on the order of 10 μm. Compared to the track pitch, thedisplacement between the standard track 152 and the track 154 isrelatively small to such an extent that the two tracks overlap.Therefore, a data format of magnetic tape for a plurality of tracks canbe designed for flexible recording and reproducing.

As another example, a wide pitch head can be used for the plurality ofthe tracks on the magnetic tape. The wide pitch head can trace both thestandard track 152 and the track 154 because the width of the headexceeds the track pitch.

According to the present example, both of the above-mentioned methods Aand B can be selected.

EXAMPLE 6

A reproducing device reproducing data recorded in a recording formatenabling a plurality of track angles will be described.

As is apparent from the track pattern of FIG. 15, in the case where theangle of the recorded track is different from the angle of a headscanning at a time of reproducing data on the recorded track, it isdifficult to reproduce the correct recorded data. In the presentexample, in order to reproduce signals from the tracks having varioustrack angles, the cylinder rotation speed which is higher than usual isused. According to this method, it is difficult to reproduce all of thedata recorded in one track by only one head scan. However, since thenumber of head scans is increased, all of the data recorded in one trackcan be reproduced by scanning one track a plurality of times. Thus,according to the present example, data can be reproduced from trackswith any track angles. Because of this, even in the case where thecylinder rotation speed is not limited at the time of recording data asdescribed in Example 5, correct data can be reproduced. The effectsobtained by increasing the cylinder rotation speed can also be obtainedby increasing the number of heads mounted on the cylinder.

FIG. 16 is a block diagram of a reproducing device of Example 6according to the present invention. In FIG. 16, the reference numeral161 denotes a magnetic tape, 162 denotes an error correction shufflingdevice, 163 denotes a memory, 164 denotes a high efficiency decoder, and165 denotes an output portion.

Signals reproduced from the magnetic tape 161 are input to the errorcorrection shuffling device 162. The error correction shuffling device162 corrects a part or all of the error correction code and transfersdecoded data to the memory 163. The data stored in the memory 163 isread by the error correction shuffling device 162 so as to be shuffledin the order suitable for the processing in the high efficiency decoder164. If required, the data thus read is subjected to error correction bythe error correction shuffling device 162 and is input to the highefficiency decoder 164. The high efficiency decoder 164 decodes theinput data, converted it into video data, audio data, etc. and outputsthe converted data to the output portion 165.

As described above, according to the present example, the reproduceddata can be shuffled when it is read from the memory 163 by controllingan address of the data or a timing of retrieving the data. In general,the data reproduced from the magnetic tape 161 includes address data.The address data indicates which portion of the tracks the reproduceddata has been recorded in. In the case where data is reproduced in theorder different from the usual order due to the off-tracking, the datafrom the memory 163 is shuffled in the correct order based on theaddress data. Such shuffling can be utilized for high-speedreproduction, slow reproduction functions of DVCRs.

EXAMPLE 7

A reproducing device of Example 7 according to the present inventionwill be described. In the present example, data can be reproduced by atleast two kinds of data rates, i.e., a normal data rate and a data ratelower than the normal one. Here, it is assumed that the normal data rateis 24 Mbit/s and the low data rate is 8 Mbit/s.

In the case where the data rate is 8 Mbit/s, the tape traveling speedand the number of tracks reproduced per unit period become ⅓ of those atthe time when data is reproduced at the normal data rate (i.e., 24Mbit/s). As described in Example 4, there are two methods for recordingsuch low-rate signals. The track angles are different between thesemethods. For this reason, as described in Example 5, data corded by bothof these methods cannot be reproduced by a normal reproducing method. Inthe present example, in the case where the low-rate signals arereproduced, the tape traveling speed is made ⅓ of that at a time whendata is reproduced at the normal data rate, and the rotation number ofthe cylinder and the number of the effective heads are made the same asthose at the time when data is reproduced at the normal data rate.

As a result, even though each reproducing head cannot exactly trace thetracks, the number of the effective heads becomes three times thatrequired for reproducing data; therefore, sufficient amount of data canbe reproduced.

FIG. 17 is a block diagram of a reproducing device of Example 7according to the present invention. In FIG. 17, the reference numeral171 denotes a magnetic tape, 172 denotes an error correction shufflingdevice, 173 denotes a memory, 174 denotes a high efficiency decoder, 175denotes an output portion, 176 denotes a tape traveling controller, and177 denotes a data rate input portion. A data rate to be reproduced isinput to the data rate input portion 177. The data rate is then input tothe tape traveling controller 176. In the case where the data rate is anormal data rate (i.e., 24 Mbit/s), the magnetic tape 171 travels at anormal tape traveling speed; and in the case where the data rate is alow data rate (i.e., 8 Mbit/s), the magnetic tape travels at a tapetraveling speed which is ⅓ of the normal one. In the present example,the rotation number of the cylinder and the number of the effectiveheads at the time when data is reproduced at the low data rate are thesame as those at the time when data is reproduced at the normal datarate.

The signals reproduced from the magnetic tape 171 are input to the errorcorrection shuffling device 172. The error correction shuffling device172 corrects a part or all of the error correction code and transfersthe decoded data to the memory 173. The data stored in the memory 173 isread by the error correction shuffling device 172 so as to be shuffledin the order suitable for the processing in the high efficiency decoder174. If required, the data thus read is subjected to the errorcorrection by the error correction shuffling device 172 and is input tothe high efficiency decoder 174. The high efficiency decoder 174 decodesthe input data, converted it into video data, audio data, etc. andoutputs the converted data to the output portion 175.

As described above, according to the present example, the reproduceddata from the memory 173 can be shuffled. In the case where data isreproduced in the order different from the usual order due to theoff-tracking, the data from the memory 173 is shuffled in the correctorder based on the address data. Such a method for reproducing low-ratesignals is similar to a method by which normal-rate signals arereproduced at a slow rate (i.e., ⅓ times).

As described above, in the reproducing device of Example 7, stablereproduction of data can be made possible irrespective of the trackangles by reproducing the low-rate signals and the normal-rate signalsin almost the same reproducing method.

EXAMPLE 8

FIG. 18 is a block diagram of a recording device of Example 8 accordingto the present invention. In FIG. 18, the reference numeral 181 denotesan input portion for video signals or audio signals, 182 denotes a timeaxis compressor, 183 denotes a high efficiency encoder, 184 denotes anerror correction encoder, 185 denotes a magnetic tape, and 186 denotes adata rate input portion. Video signals or audio signals are input fromthe input portion 181 to the time axis compressor 182. In the case wherea value, which indicates that the input video signals or the audiosignals are those to be reproduced at a normal data rate, is input, theinput data (i.e., the video signals or the audio signals) is output tothe high efficiency encoder 183 instead of being subjected to time axiscompression by the time axis compressor 182. In the case where a value,which indicates that the input video signals or the audio signals arethose to be reproduced at a data rate lower than the normal one, isinput, the input data (i.e., the video signals or the audio signals) issubjected to time axis compression by the time axis compressor 182 andis output to the high efficiency encoder 183. For example, the low-ratesignals represented by the solid line of FIG. 12 are subjected to timeaxis compression to be converted into the normal-rate signals asrepresented by the dotted line. Here, time axis compression refers tothe conversion of signals having a low data rate into signals having alarge amount of data rate by utilizing a memory device or a hard diskdevice, etc.

As described above, during reproducing, the data rate of the low-ratesignals is increased by the time axis compression before high efficiencycoding. By doing so, the data rate after the high efficiency coding ismade almost the same as the normal data rate. More specifically, thehigh efficiency encoder 183 decreases the compression ratio of thenormal-rate signals and increases the compression ratio of the low-ratesignals. The data after the high efficiency coding is subjected to theerror correction coding by the error correction encoder 184 and isrecorded on the magnetic tape 185.

As described above, in the present example, since the normal-ratesignals and the low-rate signals can be recorded at almost the same datarate after the high efficiency coding, a recording processing circuit issimplified. In the construction shown in FIG. 18, signals are input andthen are subjected to time axis compression. It is also possible thatdata which has been subjected to time axis compression is input.Furthermore, data which is subjected to time axis compression after highefficiency coding can be directly input to the error correction encoder184.

In the case where the low-rate signals are recorded according to thepresent example, the angle of the tracks on the magnetic tape becomesdifferent from that in the case where the same data is recorded withouttime axis compression. However, if the reproducing device of Example 6or 7 is applied, the angle of the tracks in both cases can be reproducedby the same reproducing device.

Furthermore, the control during reproducing data can be made correct byrecording, on the magnetic tape, data indicating the difference in angleof the tracks depending upon the recording methods, the tape travelingspeed during recording, the time axis compression ratio, the data rate,etc.

EXAMPLES 9

FIG. 19 shows a recording device of Example 9 according to the presentinvention. In FIG. 19, the reference numeral 191 denotes an inputportion for video signals or audio signals, 192 denotes a highefficiency encoder, 193 denotes an error correction encoder, 194 denotesa magnetic tape, 195 denotes a data rate input portion, and 196 denotesa tape traveling controller. Video signals or audio signals input fromthe input portion 191 are subjected to high efficiency coding by thehigh efficiency encoder 192 based on the data rate for recording orreproducing input from the data rate input portion 195, and are encodedby the error correction encoder 193 to be recorded on the magnetic tape194.

The number of tracks in which low-rate signals are recorded in apredetermined period of time is smaller than that for recordingnormal-rate signals. In general, the tape traveling speed is varied inproportion with the number of tracks in which data is recorded in apredetermined time of period. In the present example, the tape travelingspeed is set to be lower by the tape traveling controller 196 in thecase of the low-rate signals. Because of this, when the low-rate signalsare recorded, the track pitch becomes smaller than that for recordingthe normal-rate signals. As a result, the amount of tape to be consumedcan be decreased.

In the case where data is recorded with a track pitch smaller than usualin accordance with the present example, the angle of the tracks on themagnetic tape becomes different from that in the case where data isrecorded with a normal track pitch. However, if the reproducing deviceof Example 6 or 7 is applied, data can be reproduced by the samereproducing device in both cases.

Control during reproducing data can be made correct by recording dataindicating the difference in width of the tracks depending upon therecording methods, the tape traveling speed during recording, the timeaxis compression ratio, the data rate, etc.

EXAMPLES 10

FIG. 20 shows a recording and reproducing device of Example 10 accordingto the present invention. In FIG. 20, the reference numeral 201 denotesa magnetic tape, 202 denotes an error correction deshuffling device, 203denotes a transmission path, 204 denotes an error correction encoder,and 205 denotes a magnetic tape.

The left side of the transmission path 203 corresponds to a reproducingdevice, and the right side of the transmission path 203 corresponds to arecording device. Data reproduced from the magnetic tape 201 by thereproducing device is subjected to error correction and the like by theerror correction deshuffling device 202. The error-corrected data isinput to the error correction encoder 204 of the recording devicethrough the transmission path 203. The data is subjected to errorcorrection coding by the error correction encoder 204 and is recorded onthe magnetic tape 205.

In the present example, low-rate signals to be reproduced by thereproducing device at a data rate lower than the normal data rate arealso reproduced at a data rate equivalent to the normal data rate(normal tape traveling speed) and is output to the recording device. Inthe recording device, both of the normal-rate signals and the low-ratesignals are recorded on the magnetic tape 205 at the identical data rate(tape traveling speed).

Thus, the low-rate signals can also be copied at a data rate equivalentto the normal data rate. For example, in the case where the data rate ofthe normal-rate signals is 24 Mbit/s and the data rate of the low-ratesignals is 8 Mbit/s, the low-rate signals can be copied three timesfaster than that in the case where they are copied at a low data rate.Such high-speed copying enables a great reducion of the manufacturingperiod of pre-recorded soft tapes and manufacturing cost thereof. Inaddition, data recorded in this way can be reproduced by the reproducingdevice of Example 6 or 7.

It is noted that the normal data rate and the low data rate described inExamples 4 to 10 can be set to be a plurality of values, respectively inone device.

As is apparent from the above description, in the reproducing deviceaccording to the present invention, much more data than that reproducedby a normal method can be reproduced. Consequently, even in the casewhere the recording tracks have different angles, all of the data in thetracks can be reproduced. Since the limitation of the recording method(especially, the track angles) can be alleviated by using thereproducing device of the present invention, the reproducing device ofthe present invention can be applied to various kinds of recordingmethods.

Regarding the low-rate signals, data more than that required forreproducing the low-rate signals can be reproduced, and even in the casewhere the recording track angles are different, all of the data in thetracks can be reproduced. Thus, by using the reproducing device of thepresent invention, the limitation of the recording method with respectto the low-rate signals can be alleviated. Furthermore, the reproductionof the low-rate signals can be performed by the same processing as slowreproduction of the normal-rate signals.

According to the recording device of the present invention, the low-ratesignals are subjected to time axis compression to be recorded at anormal data rate in a short period of time, and hence pre-recorded softtapes and the like can be produced in a short period of time withoutusing a special recording device. In addition, data can be recorded witha track pitch smaller than usual, reducing the consumption amount of apre-recorded soft tape and the like. Furthermore, data can be reproducedat a data rate higher than usual and the reproduced data can be recordedat the higher data rate, enabling high-speed copying.

EXAMPLE 11

A recording device of Example 11 and the relationship between the trackpitch and the tape traveling speed will be described with reference toFIGS. 21 and 22, respectively. In FIG. 21, the reference numeral 211denotes a head, 212 denotes a rotary cylinder, and 213 denotes a tape.In FIG. 22, the reference numeral 152 denotes a standard track, 221denotes a head moving vector, 222 denotes a tape traveling vector, 150denotes a conventional predetermined head moving vector, and 151 denotesa conventional predetermined tape traveling vector.

The rotary cylinder 212 provided with the head 211 rotates to formtracks on the tape 213, whereby data is recorded. The rotation axis tiltangle relative to the center line of the tape 213 is set so that thedirection of the head moving vector 221 (i.e., the direction in whichthe head 211 moves) becomes a desired direction associated with therotation of the rotary cylinder 212 having the rotation axis.

The tape traveling speed is determined by the data rate of signals to berecorded. The tape traveling vector 222 is determined based on thedistance which the tape travels for the time period required for formingone track. The direction of the tape traveling vector 222 is in parallelwith the longitudinal direction of the tape. Since the standard track150 has already been determined, the desired direction of the headmoving vector 221 is determined based on the tape traveling vector 222so as to form the standard track 150.

According to the above-mentioned construction, the standard track 152having a predetermined track angle can be formed and data having a datarate other than the normal one can be recorded.

FIG. 23 is a block diagram of a recording device of the secondconstruction example of Example 11 according to the present invention.The reference numeral 231 denotes a receiving signal input portion, 232denotes a data recording circuit, 233 denotes a rotary cylinder, 234 aand 234 b denote recording heads, 235 denotes a tape, 236 denotes aswitch, and 237 denotes a tape traveling control circuit. Here, a180°-opposing double heads is used, and the tape 235 is wrapped aroundthe rotary cylinder 233 by 180°. The recording heads 234 a and 234 bhave respectively different azimuth angles.

In the recording device, data having a data rate other than the normalone is input to the receiving signal input portion 231. The datarecording circuit 232 performs recording signal processing such as errorcorrection coding, modulation and demodulation, and data shuffling togenerate recording signals, and output the recording signals inaccordance with the recording timing. The recording signals are recordedon the tape 235 by the recording heads 234 a and 234 b provided in therotary cylinder 233. As described in Example 1, the angle formed by therotation axis of the rotary cylinder 233 and the center line of the tape235 is set to be a desired value determined the data rate of input data.The switch 236 connects the recording head which is recording data tothe data recording circuit 232. When the data rate other than the normalone is k1/k2 or less (k1 and k2 are integers) of the normal data rate,the tape traveling control circuit 237 makes the tape traveling speedk1/k2 times the normal speed. At the same time, the tape travelingcontrol circuit 237 controls the rotation tilt angle of the rotarycylinder 212 in accordance with the tape traveling speed.

FIGS. 24A to 24D are timing diagrams in which the period for actuallyrecording data by each recording head is represented by “High” and theperiod for recording no data by each recording head is represented by“Low”. FIG. 24A is a timing diagram in which data is recorded at anormal data rate. FIG. 24B is a timing diagram in which k1 is 1 and k2is 3; FIG. 24C is a timing diagram in which k1 is 1 and k2 is 5; andFIG. 24D is a timing diagram in which k1 is 1 and k2 is 7. When signalshaving such a normal data rate are recorded, the tape traveling speedshould be known at the time of reproducing data. For the purpose ofknowing the tape traveling speed, the tape traveling speed data may beinput to the reproducing device from outside every time data isreproduced. Correct tape traveling speed data can be always obtained byrecording data indicating the tape traveling speed in the part of therecording signals by the data recording circuit 32.

According to the above-mentioned construction, even in the case wheredata having a data rate other than the normal one is input, tracks inaccordance with the standard can be formed. In particular, when the datarate is low, long-time recording is made possible and dubbing recordingis made possible in a short period of time by allowing a tape which issubjected to long-time recording to travel at a normal speed.

FIG. 25 is a blocs diagram of a recording device of the thirdconstruction example of Example 11 according to the present invention.The reference numeral 231 denotes a receiving signal input portion, 232denotes a data recording circuit, 233 denotes a rotary cylinder, 234 aand 234 b denote recording heads, 235 denotes a tape, 236 denotes aswitch, 237 denotes a tape traveling control circuit, and 238 denotes adata rate detecting circuit. The receiving signal input portion 231, thedata recording circuit 232, the rotary cylinder 233, the recording head234 a and 234 b, the tape 235, the switch 236, and the tape travelingcontrol circuit 237 function in the same way as in the secondconstruction example. The data rate of input data is detected by thedata rate detecting circuit 238. Tape traveling speed is determinedbased on the detected data rate. Then, in accordance with the determineddata, the data recording circuit 232 and the tape traveling controlcircuit 237 are controlled.

According to the above-mentioned construction, data having a pluralityof data rates (which may contain a normal data rate) other than a normalone can be recorded.

The block construction of the recording device of the present example ismerely an example. The same effects can be obtained with anyconstructions. In the present example, a double-azimuth 180°-opposingdouble heads is used, and the tape is wrapped around the cylinder by180°. In this construction, k1 is 1, and k2 is limited to an odd number.When paired heads, i.e., a combination of a head A and a head B mountedadjacent to each other is used, k2 can be an arbitrary number. In thecase where two paired double-azimuth 180°-opposing double heads are usedand the tape winds around the cylinder by 180°, k1 can be made 2.Alternatively, in the case where data is recorded with a guard bandinstead of any azimuth, k1 and k2 can be any numbers even in anyconstructions of heads.

In the present example, the tilt angle of the rotation axis of therotary cylinder is varied. In the case where a recording head utilizing,for example, a piezoelectric element is used, tracks in accordance withstandards can be formed by moving the recording head in parallel withthe rotation axis of the rotary cylinder while recording tracks with thesame mechanism of the rotary cylinder.

In the case where the data rate of input data is smaller than k1/k2 of anormal data rate of the recording device, the data recording circuit 232can add data corresponding to the difference between the data rate ofthe input data and k1/k2 of the normal data rate. For example, the datarecording circuit 232 can perform processings such as the addition of afixed value, the addition of error correction coding, andmultiple-writing by selecting important information.

In the second and third construction examples, the recording heads 234 aand 234 b are used. It is also possible to use heads for recording andreproducing data.

In the present example, the tape traveling speed data is recorded on thetape. In the case where an auxiliary storage medium (e.g., a memory, amagnetic tape) is provided in a cassette accommodating the tape, suchdata can be stored in the auxiliary storage medium. By doing so, correcttape traveling speed data can be obtained before starting the operationof reproducing.

As described above, in the recording device of the present example,since the track angle of the tracks to be recorded can be maintained atthe same angle even though the tape travels at any speed, data having adata rate other than a normal one can be appropriately recorded. Thus,the effects for practical use are great.

Furthermore, in the case of the low-rate data, long-time recording andfast dubbing recording by allowing the tape to travel at a normal speedare made possible.

The recording and reproducing devices in above-mentioned examples may bedevices designed specifically for recording or reproducing data, or maybe recording/reproducing device in which a recording portion and areproducing portion cannot be simultaneously operated. Even in thiscase, the same effects as those in the above examples can be obtained.

In the above-mentioned examples 1 through 11, setting the recording datarate to be proportional to the traveling speed of the magnetic tapeallows using the conventional recording format. Also, the recordingdevice can record auxiliary digital data on the recording medium withdigital data for audio and video signals. The auxiliary digital dataincludes: a track angle; a track pitch; a traveling speed of therecording medium; a rotation number of the rotary cylinder. Theauxiliary digital data can be stored in an storage medium provided in acassette accommodating the recording medium.

Furthermore, the examples are described taking a VCR as an example;however, the same recording method can be applied to devices other thanVCRs. These examples can be combined.

Various constructions other than those of the above-mentioned examplescan be applied to the present invention. For example, theabove-mentioned hardware construction can be realized by using softwarehaving the identical function with that of the hardware.

According to the present invention, it is not necessary to limit thekinds of data to be recorded. On the other hand, in the case where thedevice of the present invention tries to reproduce data which isrecorded on the magnetic tape in a format which the device cannotreproduce, the device performs an abnormal termination processing.

As described above, the recording and/or reproducing device of thepresent invention can deal with various video signals with a simplifiedconstruction. Furthermore, according to the present invention, thelimitation during recording data is greatly alleviated, so that therecording device can be made simplified and varied. Thus, the practicaleffects of the present invention are great.

Various other modifications will be apparent to and can be readily madeby those skilled in the art without departing from the scope and spiritof this invention. Accordingly, it is not intended that the scope of theclaims appended hereto be limited to the description as set forthherein, but rather that the claims be broadly construed.

What is claimed is:
 1. A digital data reproducing device for reproducingdigital data from a recording medium by using a head mounted on a rotarycylinder, the device being capable of reproducing first data intendedfor reproduction at a predetermined first rate, capable of reproducingsecond data intended for reproduction at a second rate less than thepredetermined first rate, the first data being recorded on tracks havinga first track angle, and the second data being recorded on tracks havinga second track angle less than the first track angle, wherein the devicecomprises: data reproducing means for reproducing the second data at arate higher than the second rate by rotation of the rotary cylinder at arotation rate substantially equal to the rotation rate for reproducingthe first data at said predetermined first rate; and data output meansfor selectively outputting required data among the reproduced digitaldata; characterized in that: the data reproducing means reproduces thesecond data recorded on the tracks having the second track angle byrotating the rotary cylinder so as to scan each track having the secondtrack angle a plurality of times at a head scanning angle differing fromthe second track angle, and the data output means comprises a memory inwhich the second data reproduced by the data reproduction means isstored, and means for shuffling the reproduced second data foroutputting from the memory.
 2. A digital data reproducing deviceaccording to claim 1, wherein the data rate is in proportion with atraveling speed of the recording medium.